Some known air intakes for aircraft engines include an inlet that generally conforms to a surface contour of the aircraft adjacent the intake. Such intakes may include a filter, air permeable cover or similar device that has an outer surface generally conformal to the local contour of the aircraft skin.
In some cases, a dynamic pressure of air flow into such an intake varies significantly with the flight condition of the aircraft. For example, some rotary aircraft include an air intake that faces generally upward, such that the outer surface of the air permeable cover is generally perpendicular to air flow at the intake while the aircraft is hovering, and generally parallel to airflow at the intake when the aircraft is in forward flight. As a result, the intake airflow in the forward flight condition has a significantly lower dynamic pressure than in the hover condition, which may result in comparatively reduced engine performance, or negatively affect performance, in forward flight. In at least some cases, it may be desirable to at least partially recover the dynamic pressure at the air intake in the forward flight condition. Moreover, an air intake that faces generally upward tends to expose the filter media to ultraviolet radiation from the sun, or other environmental conditions which may accelerate the degradation of the filter media and necessitate more frequent replacements of the filter assembly and/or filter media. Environmental conditions such as hail, driving rain, heavy snow or other airborne debris can damage the filter assembly and or filter media.
This Background section is intended to introduce the reader to various aspects of art that may be related to various aspects of the present disclosure, which are described and/or claimed below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present disclosure. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art.